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"""Implementations of interoperability test methods."""

import enum
import json
import os
import threading
import time

from oauth2client import client as oauth2client_client

import grpc
from grpc.beta import implementations

from src.proto.grpc.testing import empty_pb2
from src.proto.grpc.testing import messages_pb2
from src.proto.grpc.testing import test_pb2

_INITIAL_METADATA_KEY = "x-grpc-test-echo-initial"
_TRAILING_METADATA_KEY = "x-grpc-test-echo-trailing-bin"

def _maybe_echo_metadata(servicer_context):
  """Copies metadata from request to response if it is present."""
  invocation_metadata = dict(servicer_context.invocation_metadata())
  if _INITIAL_METADATA_KEY in invocation_metadata:
    initial_metadatum = (
        _INITIAL_METADATA_KEY, invocation_metadata[_INITIAL_METADATA_KEY])
    servicer_context.send_initial_metadata((initial_metadatum,))
  if _TRAILING_METADATA_KEY in invocation_metadata:
    trailing_metadatum = (
      _TRAILING_METADATA_KEY, invocation_metadata[_TRAILING_METADATA_KEY])
    servicer_context.set_trailing_metadata((trailing_metadatum,))

def _maybe_echo_status_and_message(request, servicer_context):
  """Sets the response context code and details if the request asks for them"""
  if request.HasField('response_status'):
    servicer_context.set_code(request.response_status.code)
    servicer_context.set_details(request.response_status.message)

class TestService(test_pb2.TestServiceServicer):

  def EmptyCall(self, request, context):
    _maybe_echo_metadata(context)
    return empty_pb2.Empty()

  def UnaryCall(self, request, context):
    _maybe_echo_metadata(context)
    _maybe_echo_status_and_message(request, context)
    return messages_pb2.SimpleResponse(
        payload=messages_pb2.Payload(
            type=messages_pb2.COMPRESSABLE,
            body=b'\x00' * request.response_size))

  def StreamingOutputCall(self, request, context):
    _maybe_echo_status_and_message(request, context)
    for response_parameters in request.response_parameters:
      yield messages_pb2.StreamingOutputCallResponse(
          payload=messages_pb2.Payload(
              type=request.response_type,
              body=b'\x00' * response_parameters.size))

  def StreamingInputCall(self, request_iterator, context):
    aggregate_size = 0
    for request in request_iterator:
      if request.payload is not None and request.payload.body:
        aggregate_size += len(request.payload.body)
    return messages_pb2.StreamingInputCallResponse(
        aggregated_payload_size=aggregate_size)

  def FullDuplexCall(self, request_iterator, context):
    _maybe_echo_metadata(context)
    for request in request_iterator:
      _maybe_echo_status_and_message(request, context)
      for response_parameters in request.response_parameters:
        yield messages_pb2.StreamingOutputCallResponse(
            payload=messages_pb2.Payload(
                type=request.payload.type,
                body=b'\x00' * response_parameters.size))

  # NOTE(nathaniel): Apparently this is the same as the full-duplex call?
  # NOTE(atash): It isn't even called in the interop spec (Oct 22 2015)...
  def HalfDuplexCall(self, request_iterator, context):
    return self.FullDuplexCall(request_iterator, context)


def _expect_status_code(call, expected_code):
  if call.code() != expected_code:
    raise ValueError(
      'expected code %s, got %s' % (expected_code, call.code()))


def _expect_status_details(call, expected_details):
  if call.details() != expected_details:
    raise ValueError(
      'expected message %s, got %s' % (expected_details, call.details()))


def _validate_status_code_and_details(call, expected_code, expected_details):
  _expect_status_code(call, expected_code)
  _expect_status_details(call, expected_details)


def _validate_payload_type_and_length(response, expected_type, expected_length):
  if response.payload.type is not expected_type:
    raise ValueError(
      'expected payload type %s, got %s' %
          (expected_type, type(response.payload.type)))
  elif len(response.payload.body) != expected_length:
    raise ValueError(
      'expected payload body size %d, got %d' %
          (expected_length, len(response.payload.body)))


def _large_unary_common_behavior(
    stub, fill_username, fill_oauth_scope, call_credentials):
  size = 314159
  request = messages_pb2.SimpleRequest(
      response_type=messages_pb2.COMPRESSABLE, response_size=size,
      payload=messages_pb2.Payload(body=b'\x00' * 271828),
      fill_username=fill_username, fill_oauth_scope=fill_oauth_scope)
  response_future = stub.UnaryCall.future(
      request, credentials=call_credentials)
  response = response_future.result()
  _validate_payload_type_and_length(response, messages_pb2.COMPRESSABLE, size)
  return response


def _empty_unary(stub):
  response = stub.EmptyCall(empty_pb2.Empty())
  if not isinstance(response, empty_pb2.Empty):
    raise TypeError(
        'response is of type "%s", not empty_pb2.Empty!', type(response))


def _large_unary(stub):
  _large_unary_common_behavior(stub, False, False, None)


def _client_streaming(stub):
  payload_body_sizes = (27182, 8, 1828, 45904,)
  payloads = (
      messages_pb2.Payload(body=b'\x00' * size)
      for size in payload_body_sizes)
  requests = (
      messages_pb2.StreamingInputCallRequest(payload=payload)
      for payload in payloads)
  response = stub.StreamingInputCall(requests)
  if response.aggregated_payload_size != 74922:
    raise ValueError(
        'incorrect size %d!' % response.aggregated_payload_size)


def _server_streaming(stub):
  sizes = (31415, 9, 2653, 58979,)

  request = messages_pb2.StreamingOutputCallRequest(
      response_type=messages_pb2.COMPRESSABLE,
      response_parameters=(
          messages_pb2.ResponseParameters(size=sizes[0]),
          messages_pb2.ResponseParameters(size=sizes[1]),
          messages_pb2.ResponseParameters(size=sizes[2]),
          messages_pb2.ResponseParameters(size=sizes[3]),
      )
  )
  response_iterator = stub.StreamingOutputCall(request)
  for index, response in enumerate(response_iterator):
    _validate_payload_type_and_length(
        response, messages_pb2.COMPRESSABLE, sizes[index])


def _cancel_after_begin(stub):
  sizes = (27182, 8, 1828, 45904,)
  payloads = (messages_pb2.Payload(body=b'\x00' * size) for size in sizes)
  requests = (messages_pb2.StreamingInputCallRequest(payload=payload)
              for payload in payloads)
  response_future = stub.StreamingInputCall.future(requests)
  response_future.cancel()
  if not response_future.cancelled():
    raise ValueError('expected call to be cancelled')


class _Pipe(object):

  def __init__(self):
    self._condition = threading.Condition()
    self._values = []
    self._open = True

  def __iter__(self):
    return self

  def __next__(self):
    return self.next()

  def next(self):
    with self._condition:
      while not self._values and self._open:
        self._condition.wait()
      if self._values:
        return self._values.pop(0)
      else:
        raise StopIteration()

  def add(self, value):
    with self._condition:
      self._values.append(value)
      self._condition.notify()

  def close(self):
    with self._condition:
      self._open = False
      self._condition.notify()

  def __enter__(self):
    return self

  def __exit__(self, type, value, traceback):
    self.close()


def _ping_pong(stub):
  request_response_sizes = (31415, 9, 2653, 58979,)
  request_payload_sizes = (27182, 8, 1828, 45904,)

  with _Pipe() as pipe:
    response_iterator = stub.FullDuplexCall(pipe)
    for response_size, payload_size in zip(
        request_response_sizes, request_payload_sizes):
      request = messages_pb2.StreamingOutputCallRequest(
          response_type=messages_pb2.COMPRESSABLE,
          response_parameters=(
              messages_pb2.ResponseParameters(size=response_size),),
          payload=messages_pb2.Payload(body=b'\x00' * payload_size))
      pipe.add(request)
      response = next(response_iterator)
      _validate_payload_type_and_length(
          response, messages_pb2.COMPRESSABLE, response_size)


def _cancel_after_first_response(stub):
  request_response_sizes = (31415, 9, 2653, 58979,)
  request_payload_sizes = (27182, 8, 1828, 45904,)
  with _Pipe() as pipe:
    response_iterator = stub.FullDuplexCall(pipe)

    response_size = request_response_sizes[0]
    payload_size = request_payload_sizes[0]
    request = messages_pb2.StreamingOutputCallRequest(
        response_type=messages_pb2.COMPRESSABLE,
        response_parameters=(
            messages_pb2.ResponseParameters(size=response_size),),
        payload=messages_pb2.Payload(body=b'\x00' * payload_size))
    pipe.add(request)
    response = next(response_iterator)
    # We test the contents of `response` in the Ping Pong test - don't check
    # them here.
    response_iterator.cancel()

    try:
      next(response_iterator)
    except grpc.RpcError as rpc_error:
      if rpc_error.code() is not grpc.StatusCode.CANCELLED:
        raise
    else:
      raise ValueError('expected call to be cancelled')


def _timeout_on_sleeping_server(stub):
  request_payload_size = 27182
  with _Pipe() as pipe:
    response_iterator = stub.FullDuplexCall(pipe, timeout=0.001)

    request = messages_pb2.StreamingOutputCallRequest(
        response_type=messages_pb2.COMPRESSABLE,
        payload=messages_pb2.Payload(body=b'\x00' * request_payload_size))
    pipe.add(request)
    time.sleep(0.1)
    try:
      next(response_iterator)
    except grpc.RpcError as rpc_error:
      if rpc_error.code() is not grpc.StatusCode.DEADLINE_EXCEEDED:
        raise
    else:
      raise ValueError('expected call to exceed deadline')


def _empty_stream(stub):
  with _Pipe() as pipe:
    response_iterator = stub.FullDuplexCall(pipe)
    pipe.close()
    try:
      next(response_iterator)
      raise ValueError('expected exactly 0 responses')
    except StopIteration:
      pass


def _status_code_and_message(stub):
  details = 'test status message'
  code = 2
  status = grpc.StatusCode.UNKNOWN # code = 2

  # Test with a UnaryCall
  request = messages_pb2.SimpleRequest(
      response_type=messages_pb2.COMPRESSABLE,
      response_size=1,
      payload=messages_pb2.Payload(body=b'\x00'),
      response_status=messages_pb2.EchoStatus(code=code, message=details)
  )
  response_future = stub.UnaryCall.future(request)
  _validate_status_code_and_details(response_future, status, details)

  # Test with a FullDuplexCall
  with _Pipe() as pipe:
    response_iterator = stub.FullDuplexCall(pipe)
    request = messages_pb2.StreamingOutputCallRequest(
        response_type=messages_pb2.COMPRESSABLE,
        response_parameters=(
            messages_pb2.ResponseParameters(size=1),),
        payload=messages_pb2.Payload(body=b'\x00'),
        response_status=messages_pb2.EchoStatus(code=code, message=details))
    pipe.add(request)   # sends the initial request.
  # Dropping out of with block closes the pipe
  _validate_status_code_and_details(response_iterator, status, details)


def _unimplemented_method(test_service_stub):
  response_future = (
      test_service_stub.UnimplementedCall.future(empty_pb2.Empty()))
  _expect_status_code(response_future, grpc.StatusCode.UNIMPLEMENTED)


def _unimplemented_service(unimplemented_service_stub):
  response_future = (
      unimplemented_service_stub.UnimplementedCall.future(empty_pb2.Empty()))
  _expect_status_code(response_future, grpc.StatusCode.UNIMPLEMENTED)


def _custom_metadata(stub):
  initial_metadata_value = "test_initial_metadata_value"
  trailing_metadata_value = "\x0a\x0b\x0a\x0b\x0a\x0b"
  metadata = (
      (_INITIAL_METADATA_KEY, initial_metadata_value),
      (_TRAILING_METADATA_KEY, trailing_metadata_value))

  def _validate_metadata(response):
    initial_metadata = dict(response.initial_metadata())
    if initial_metadata[_INITIAL_METADATA_KEY] != initial_metadata_value:
      raise ValueError(
        'expected initial metadata %s, got %s' % (
            initial_metadata_value, initial_metadata[_INITIAL_METADATA_KEY]))
    trailing_metadata = dict(response.trailing_metadata())
    if trailing_metadata[_TRAILING_METADATA_KEY] != trailing_metadata_value:
      raise ValueError(
        'expected trailing metadata %s, got %s' % (
            trailing_metadata_value, initial_metadata[_TRAILING_METADATA_KEY]))

  # Testing with UnaryCall
  request = messages_pb2.SimpleRequest(
      response_type=messages_pb2.COMPRESSABLE,
      response_size=1,
      payload=messages_pb2.Payload(body=b'\x00'))
  response_future = stub.UnaryCall.future(request, metadata=metadata)
  _validate_metadata(response_future)

  # Testing with FullDuplexCall
  with _Pipe() as pipe:
    response_iterator = stub.FullDuplexCall(pipe, metadata=metadata)
    request = messages_pb2.StreamingOutputCallRequest(
        response_type=messages_pb2.COMPRESSABLE,
        response_parameters=(
            messages_pb2.ResponseParameters(size=1),))
    pipe.add(request)   # Sends the request
    next(response_iterator)    # Causes server to send trailing metadata
  # Dropping out of the with block closes the pipe
  _validate_metadata(response_iterator)

def _compute_engine_creds(stub, args):
  response = _large_unary_common_behavior(stub, True, True, None)
  if args.default_service_account != response.username:
    raise ValueError(
        'expected username %s, got %s' % (
            args.default_service_account, response.username))


def _oauth2_auth_token(stub, args):
  json_key_filename = os.environ[
      oauth2client_client.GOOGLE_APPLICATION_CREDENTIALS]
  wanted_email = json.load(open(json_key_filename, 'rb'))['client_email']
  response = _large_unary_common_behavior(stub, True, True, None)
  if wanted_email != response.username:
    raise ValueError(
        'expected username %s, got %s' % (wanted_email, response.username))
  if args.oauth_scope.find(response.oauth_scope) == -1:
    raise ValueError(
        'expected to find oauth scope "{}" in received "{}"'.format(
            response.oauth_scope, args.oauth_scope))


def _jwt_token_creds(stub, args):
  json_key_filename = os.environ[
      oauth2client_client.GOOGLE_APPLICATION_CREDENTIALS]
  wanted_email = json.load(open(json_key_filename, 'rb'))['client_email']
  response = _large_unary_common_behavior(stub, True, False, None)
  if wanted_email != response.username:
    raise ValueError(
        'expected username %s, got %s' % (wanted_email, response.username))


def _per_rpc_creds(stub, args):
  json_key_filename = os.environ[
      oauth2client_client.GOOGLE_APPLICATION_CREDENTIALS]
  wanted_email = json.load(open(json_key_filename, 'rb'))['client_email']
  credentials = oauth2client_client.GoogleCredentials.get_application_default()
  scoped_credentials = credentials.create_scoped([args.oauth_scope])
  # TODO(https://github.com/grpc/grpc/issues/6799): Eliminate this last
  # remaining use of the Beta API.
  call_credentials = implementations.google_call_credentials(
      scoped_credentials)
  response = _large_unary_common_behavior(stub, True, False, call_credentials)
  if wanted_email != response.username:
    raise ValueError(
        'expected username %s, got %s' % (wanted_email, response.username))


@enum.unique
class TestCase(enum.Enum):
  EMPTY_UNARY = 'empty_unary'
  LARGE_UNARY = 'large_unary'
  SERVER_STREAMING = 'server_streaming'
  CLIENT_STREAMING = 'client_streaming'
  PING_PONG = 'ping_pong'
  CANCEL_AFTER_BEGIN = 'cancel_after_begin'
  CANCEL_AFTER_FIRST_RESPONSE = 'cancel_after_first_response'
  EMPTY_STREAM = 'empty_stream'
  STATUS_CODE_AND_MESSAGE = 'status_code_and_message'
  UNIMPLEMENTED_METHOD = 'unimplemented_method'
  UNIMPLEMENTED_SERVICE = 'unimplemented_service'
  CUSTOM_METADATA = "custom_metadata"
  COMPUTE_ENGINE_CREDS = 'compute_engine_creds'
  OAUTH2_AUTH_TOKEN = 'oauth2_auth_token'
  JWT_TOKEN_CREDS = 'jwt_token_creds'
  PER_RPC_CREDS = 'per_rpc_creds'
  TIMEOUT_ON_SLEEPING_SERVER = 'timeout_on_sleeping_server'

  def test_interoperability(self, stub, args):
    if self is TestCase.EMPTY_UNARY:
      _empty_unary(stub)
    elif self is TestCase.LARGE_UNARY:
      _large_unary(stub)
    elif self is TestCase.SERVER_STREAMING:
      _server_streaming(stub)
    elif self is TestCase.CLIENT_STREAMING:
      _client_streaming(stub)
    elif self is TestCase.PING_PONG:
      _ping_pong(stub)
    elif self is TestCase.CANCEL_AFTER_BEGIN:
      _cancel_after_begin(stub)
    elif self is TestCase.CANCEL_AFTER_FIRST_RESPONSE:
      _cancel_after_first_response(stub)
    elif self is TestCase.TIMEOUT_ON_SLEEPING_SERVER:
      _timeout_on_sleeping_server(stub)
    elif self is TestCase.EMPTY_STREAM:
      _empty_stream(stub)
    elif self is TestCase.STATUS_CODE_AND_MESSAGE:
      _status_code_and_message(stub)
    elif self is TestCase.UNIMPLEMENTED_METHOD:
      _unimplemented_method(stub)
    elif self is TestCase.UNIMPLEMENTED_SERVICE:
      _unimplemented_service(stub)
    elif self is TestCase.CUSTOM_METADATA:
      _custom_metadata(stub)
    elif self is TestCase.COMPUTE_ENGINE_CREDS:
      _compute_engine_creds(stub, args)
    elif self is TestCase.OAUTH2_AUTH_TOKEN:
      _oauth2_auth_token(stub, args)
    elif self is TestCase.JWT_TOKEN_CREDS:
      _jwt_token_creds(stub, args)
    elif self is TestCase.PER_RPC_CREDS:
      _per_rpc_creds(stub, args)
    else:
      raise NotImplementedError('Test case "%s" not implemented!' % self.name)
